Cotton-substantive brighteners are commonly used in laundry detergents. Said brighteners deposit onto fabrics where they absorb ultraviolet radiant energy and reemit it as blue light. This reduces or eliminates any yellowish cast to fabrics and gives them a bright appearance. Examples of these brighteners are anionic brighteners with sulfonic acid group(s) e.g. mono- or di-sulfonic acid derivatives of bis-(tri-azinylamino)-stilbene, bis-(tri-azolyl)-stilbene and (sulfo styryl)-biphenyl.
However, it has been found to be difficult to avoid precipitation in liquid detergent compositions containing cotton-substantive brighteners in combination with polymers which exhibit dye transfer inhibiting properties. These polymers are used to complex or absorb the fugitive dyes washed out of dyed fabrics before they have the opportunity to become attached to other articles in the wash. Examples of such polymers that have been used within detergent compositions to inhibit dye transfer are vinylpyrrolidone polymers disclosed in EP-265 257 and EP-508 034.
Surprisingly, it has now been found that improved storage stability of liquid detergent compositions comprising vinylpyrrolidone polymers and cotton-substantive brighteners can be obtained by selecting well-defined type of cotton-substantive brighteners.
According to the present invention, a stable dye transfer inhibiting composition comprising a cotton-substantive brightener is provided which has improved stability upon storage.